Complex organic-like object from two splines (imported)
A simple way of achieving this is to use a combination of Solidify and Boolean modifiers.

First model your splines to match your desired profiles. In my case I started with a Nurbs Circle and then manipulated it in Edit mode to get the desired shape - one for the Top profile and another for the Right profile and rotated them and position them appropriately.



Next, convert each profile into a Mesh and, in Edit mode, select all and create a Face by pressing 'F'.

Select the 'Top' object and open the Modifiers panel and add a Solidify modifier. Increase the thickness sufficiently so that it will fully overlap with the other shape. Repeat with the 'Right' object so that the two objects overlap as shown.



Position and scale the objects so that they match - I had to stretch you're example 'Top' view to match the dimension of the 'Right' view.



Select one of the objects and add a 'Boolean' operator. Click the dropper in the Object field and click on the other object in the viewport. Set the Operation to 'Intersect'. Select the other object in the viewport and press 'H' to hide it. You should now see the generated object from the intersection of the two extruded profiles.



To tidy up the geometry of the generated mesh, right-click the object and add a Remesh modifier. Select Smooth for the Mode and reduce the Octree Depth until it doesn't quite start to distort. Enable Smooth Shading.

You could also optionally add a Subdivision Surface modifier.

Select 'Apply' on each of the modifiers to apply them (be careful to apply them in Top-to-Bottom order).

 

Once the modifiers have been applied you should unhide the hidden objects (Alt-H) and select them and delete them as they are no longer required.

You'll get better results by adding additional profiles - preferably you want at least a Top, Front and Side profile (although you could have more if you know the profile from other angles) and position them and scale them in a similar way and add in as additional Boolean modifiers in the modifier stack - eg, Solidify, Boolean1, Boolean2, Remesh, Subsurface.

The generated shape will most likely need some fine tuning in Edit mode as the profiles don't provide enough detail - in particular for concave shapes.